Electrical equipment, for example, mobile communication equipment such as mobile phones, generally have an antenna embedded therein for wireless communication.
As such an antenna device, such as the antenna device shown in FIG. 36, for example, is known (See JP 2007-274665 A).
The known antenna device 101 shown in FIG. 36 includes a base body 110 made of a synthetic resin and a known flexible printed circuit board (FPC) 120.
Herein, a first element 121 and a second element 122 each made of an electrical conductive pattern, such as a copper foil, are independently disposed on one surface of the base of the known FPC 120 (that is the surface to be attached to the base body 110). Moreover, the known FPC 120 includes a folded portion 123 which is to be arranged along a side surface position of the base body 110. A power-feeding portion, not shown, includes the folded portion 123, and an end of the power-feeding portion is connected to the second element 122. Moreover, chips 124 and 125 constituting a resonant circuit are disposed between the first element 121 and the second element 122.
A surface of the known FPC 120, on which the first element 121 and the second element 122 and the chips 124 and 125 (constituting an antenna element) are formed, is attached to a top surface 111 of the base body 110 using double-sided tape, or other securing means known to the art.
Meanwhile, an antenna device used in mobile communication equipment, such as a mobile phone, should be arranged apart from electrical conductive members, such as a circuit board embedded in the communication equipment, in order to more efficiently carry out wireless communications. Therefore, in recent years, there is a demand for arranging the antenna device in a chassis, such as a cover of the mobile communication equipment, such that the antenna device is positioned apart from the embedded circuit board. When the chassis is rectangular shaped, corners of the chassis are disposed furthest from the embedded circuit board. Therefore, it is most preferable to arrange the antenna device at a corner of the chassis. On the other hand, the corners of the chassis, such as a cover, often tend to have a curved section made of a three-dimensional curved surface.
Herein, a “three-dimensional curved surface” denotes a surface having a curved line in all planes: X-Y plane; Y-Z plane; and Z-X plane, when an object is projected onto all of them, assuming that there are X, Y, and Z axes crossing perpendicular to one another.
However, there are problems positioning the known FPC 120 shown in FIG. 36 along a curved section of a chassis having a three-dimensional curved surface.
That is, since the known FPC 120 is a tabular film member having a flat plate shape, it cannot be arranged smoothly along the curved section having the three-dimensional curved surface of the chassis. In other words, when the known FPC 120, which is a film member having a flat plate shape, is curved and then arranged along the curved section having the three-dimensional curved surface, wrinkles or distortions may occur.
On the other hand, in recent years, antennas formed by resin injection molding, each having a conductor on its surface, such as a Molded Interconnect Device (MID) antenna or a Laser Direct Structuring (LDS) antenna, have also been developed. Since the base material of the MID antenna or the LDS antenna is formed using injection molding techniques or the like, a degree of freedom in three-dimensional shape is relatively high, and therefore it is also possible to arrange it along the curved section having a three-dimensional curved surface of the chassis.
However, in the MID or the LDS antenna, since resin is injected into a mold, a certain thickness (MID antenna: approximately 1 mm, LDS antenna: approximately 0.5 mm) is needed, which does not meet the demand for downsizing.